When Neil Armstrong and David Scott disconnected Gemini VIII from its target vehicle, the spinning became faster.
The astronauts had hoped separation would help them regain control. Instead, the capsule’s reduced mass allowed the problem to accelerate.
The Gemini VIII emergency occurred on March 16, 1966, after the mission completed the first docking of two vehicles in Earth orbit. An important success had become a situation in which the crew’s vision began to blur as the spacecraft approached one rotation per second.
Gemini VIII: The wrong vehicle seemed responsible
After docking with the Agena target, the joined vehicles began moving unexpectedly. Armstrong used Gemini’s maneuvering thrusters to stop the rotation, but it resumed.
The craft was temporarily outside communications range. The crew investigated the Agena, while Armstrong noticed that Gemini’s maneuvering propellant was running low.
Scott tried cycling the Agena’s controls. It did not solve the problem. The astronauts undocked, but the fault was in Gemini: one of its maneuvering thrusters was firing when it should not have been.
Without the Agena’s additional mass, the rotation intensified. When the crew regained radio contact with a tracking ship, they reported that they were tumbling and could not stop it.
The system reserved for coming home
Armstrong shut down the orbital maneuvering system and used the separate reentry-control thrusters to halt the spin.
That action recovered control, but used much of the reentry system’s propellant. Mission rules required the flight to end once that system had been activated in this way.
Controllers arranged an emergency return. The crew splashed down in the Pacific approximately ten hours and forty-one minutes after launch. Aircraft and pararescuers supported them while the destroyer USS Leonard F. Mason approached the recovery area.
Scott’s planned spacewalk was canceled. Both men survived the shortened mission.
The most unsettling step in the sequence is the separation. It was a reasonable attempt to isolate a malfunction, yet the motion became worse because the source of the problem traveled with the astronauts’ own vehicle.
The successful response required them to stop treating the joined spacecraft as the problem and disable an entire system on the capsule itself. A backup intended for the journey through the atmosphere became the means of remaining alive in orbit long enough to make that journey.
Their first docking had worked. For a few minutes afterward, the machine surrounding them would not obey the commands needed to keep them still.
Sources and reporting
Researched reporting: an original narrative based on the published records linked below.
